Keys are normally elongated relatively planar implements having a manually grippable enlarged bow or head located at one end and a keyhole insertable longitudinally extending blade or shank at the other end. In the normal use of a key operated lock, the shank of the key is inserted into the keyhole and turned to rotate a plug or core of a lock cylinder to bring about a desired operation, such as the mechanical unlocking of a door bolt or the actuation of a machine switch. Individualized angled serrations or cuts on the key blade correspond to different sized pin tumblers or pins within the lock cylinder to necessitate a complementary match between the key and the lock before the key can be turned.
In a usual operation, the key is inserted for the full length of its shank portion into the keyway of the lock. A widening of the key between its shank and head portions ensures proper positioning. The exposed head provides an enlarged surface which is gripped by the user's fingers to exert torque for turning the key about its shank axis.
The small heads of modern keys can be difficult to grip, especially by he elderly or infirm. The turning of the small flat key typically supplied for actuating a starter or ignition switch of an automobile, for example, can be particularly troublesome for a person whose hands have been crippled by arthritis.
Some automobiles are equipped with manually grippable tabs diagonally disposed on opposite sides of a rotary keyhole member of a steering column mounted ignition switch. Such switches typically have a smaller thumb operable front tab and a larger finger operable rear tab. Although such tabs offer some relief and permit the turning force to be applied through the tabs rather than the head of the key, for the infirm hand such a solution is not adequate, still leaving the lone crippled handed driver in the embarrassing and awkward situation of having to ask a passerby to start the car.
Other automobile designs compound the difficulty by providing ignition switch locks which are recessed to be set back into the dashboard or other lock mounting surface. With such sunken switches, there is little enough room for manipulation of a key by even a person with normal dexterity, to say nothing of the added difficulties imposed on the elderly or infirm driver.
Various keyholders exist which make provision for mounting keys for movement between positions of internal stowage and positions in which the shank projects externally for insertion into a keyhole. There is a tendency for such keyholders to be made of soft pliant materials (e.g. leather or plastic), however, and to trail the key limply when the key is extended into the lock. This does not offer any key turning assistance. Other keyholders have elaborate key projecting mechanisms that require considerable agility to operate. Satisfactory keyholders of simple design that aid the crippled hand are lacking.